There is conventionally known an electric device in which a battery pack is attachable to and detachable from a device body. A power tool as an example of such an electric device is disclosed in Japanese Patent Application Publication No. 2002-254356. The power tool includes a device body in which an electric motor is provided. The device body has a grip part, and, within the grip part, a control circuit is provided for controlling the electric motor. The grip part is also provided with a device-side terminal. The device-side terminal is electrically connected to the control circuit.
A battery pack is attachable to and detachable from the grip part. The battery pack accommodates a plurality of battery cells therein. The battery pack is provided with a battery-side terminal. Upon attachment of the battery pack to the grip part, the device-side terminal is connected to the battery-side terminal. Hence, electric power of the battery cells can be supplied to the electric motor.